Switch mechanism



Se t. 27 1 1,648,798 p 927 H. G. BAXTER SWITCH MEGHANISM Filed April 18. 1922 3 Sheets-Sheet l INVENTOR ATTORNEY LTL) WITNESSES:

Sept. 27, 1927.

H. G. BAXTER SWITCH MECHANISM Filed April 1a. 1922 3 Sheets-Sheet 2 Illlll l' Il lllll INVENTOR Haro/d 6' 50/(76/1v WIT ESSES lATTORNEY Se t. 27 192 p 7 H. G. BAXTER SWITCH MECHANISM Filed April 18, 1922 3 Sheets-Sheet 3 lNvENToR Ham/0 (2T axef IATTORNEY Patented Sept. 27, 1927.

UNITED STATES HAROLD e. `BAXTER, or WILKINsRURe, PnNNsYnvANiA, AssrGNoR To 'wEsTiNc-` MANUFACTURING COMPANY, A CoRroRATioN or PENNSYL- Housn ELECTRIC & VANIA.

PATENTfoFriCE.

SWITCH iviECHANIsM.

Application filed April 18, 1922. AVSerial No. 555,128.

My invention relates to enclosed switch mechanisms and particularly to enclosed switch mechanisms of the safety type that are adapted for use in mines. Y

One object of my invention is to provide an enclosed switch mechanism wherein the housing is of sufficient strength to withstand explosions of gas within the casing and of such construction that the gases escaping,

from the casing are cooled and extinguished before they reach the atmosphere.

Another object of my invention is to provide a switch mechanism, having the above characteristics, wherein theswitch and door are so interlocked that the latter cannot be opened so long as the switch is in closed position or the 'switch closed so long as the door is in open position. Y

Another object of my invention is to provide an enclosed switch mechanism wherein the casing is made entirely of cast metal and wherein the door is provided, along its hinged edge, with means intertitting with the edge of a stationary portion of the cover for inhibiting the gas in its passage through the joint and constituting a tortuous Ipath to insure thorough cooling of the gases be fore reaching the atmosphere.

Another object ofmy invention is to provide an enclosed switch of heavy and rugged construct-ion adapted for use in mines and on mine locomotives and wherein the hinged door is provided with Ia lock that engages the housing at a plurality of remote points for securely retaining the door in closed position against the action of explosive forces within,l

the housing.`

A further object of my invention is to provide a latch for the door having ari-interlock co-operating with the switch for preventing releasingmovemeiit of the lock so long as the switch is in closed position..l

These and other objects, that will bemade apparent throughout the further description of'my invention, may be attained by means of the switch mechanism hereinafter described, and illustrated in the accompanying provides a lost-motion connection between drawings, wherein: Y Y Figure 1 is a front view of the switch mechanism showing a portion of the stationary cover removed;v` i

Figg2 is a longitudinalsection through theU switch housing, taken on the broken lineV l Fig. 3` is a transverse section through the iousing, taken on the line .III-III of Fig. i i d i Figszi and 5 are front; and` side views, respectively, of the `door-locking. plate.

Fig. 6 is a longitudinal section in enlarged scale of the switch mechanism showing the swiltcli-operating elements in sideelevation, anc i Fig. 7 is a sidoelevational v-iew of the switch mechanism showing the' exteriorly disposed interlocking cams. n Referring to the drawings, the apparatus includes a metal housing 6 upon which is secured a metal cover portion? that is attaclied to the housing by means of bolts 8. The housing is provided with a movable door 9 `having hinge brackets l0 thereon that co-operate with brackets 11 on the Vcover portion 7. `A hinge bolt 12 extends through the brackets. i f

A 'switch panel 13 is mounted within the housing and 'supports' a switchy mechanism 14: and fuse clips l5 that are adapted to receive knife-blade cartridge vfuses (not shown).

The switch 14 may be of any preferred construction and is of the oscillatory type. The` switch comprises laminated brushes 16 that are pivotedupon a shaft 17 supported on brackets 18 thatare mounted on the base 13.5 The switch'is operated by .means of `an operating rod 19 that is pivoted to the side Pill walls of thehousingandwhich extends eX- 25 that engages a slot 26 in a lever 27 that is pivotally mounted upontlie shaft 23 and the operating rod 19 andthe knee pivot 20` of the toggle. The shaft 23`is provided with Va toggle arm 28 towliich the switch f; the switch is moved to the closed position indicated in Fig. 2, the toggle links2'8 and 29 serve tov retain the switch brushes in engagement with theconta'ctl terminals 32 and 33, the toggle links, at such time, being in i the made position indicated in Fig. 2.

Vhen the operating rod 19 is turned counterclockwise, the left shoulder 30 of the floating'lever 27 engages the knee pivot of the' toggle and causes it to collapse.

l' Engagement, however, does not take Vplace until after the operating handle has been Vmoved 'a predetermined distance toward open position. The switch is closed by engagement of the right end of the floating lever 27 with the knee pivot of the toggle links after the handle-has been moved a predetermined distance toward closed position.

The switch construction above described is well known in the art and it is believed unnecessary to go into further details as to its construction. It is obvious that, when .the-toggle link is' broken, the switch is inoved to open position with a snap action.

The circuit through the switch and fuses is such that, when the switch is open, the fuse clips and fuses aie disconnected from the current source. Y

rIhe switch herein illustrated is particularly adapted for use on electric locomotives operating in mines where it is very desirable tov'eliininate any possibilty of sparks from the switches igniting the gases usually prevalent in mines. Itis, therefore, desirable to enclose all switch mechanisms in casings of such construction that Haines incidentv to explosions of gases leaking into boxes are extinguished before the gases escape therefrom.

The operating rod 19 of the switch is biased toward either open or closed position by means of a helical spring Vthat moves past dead center when moved from one position to another. This spring causes the switch to be closed with a snap action in opposition to the spring 31 which normally tends to hold the switch in open position. I The switch mechanism above described is Ypoint between the clips 15 for the fuses connected4 with the. headlight circuit. The switch 34 is .connected to an operating handle 36 by means'of a shaft 37 .that extends through a gas-tight bearing 38. l.

It is very desirable, in a switch of this character, to prevent any possibility of moving the switch to open position while the cover is in open position in order to preclude the formation of an arc while the switch is exposed to the atmosphere.

The operating rod 19 is provided wit-li a cam member 39 having an arcuate vedge 41 concentric withthe axis of rotation ofthe operating rod 19. The cam is also provided with an' arcuate edge 42 that is adapted to be moved into a position wherein it is concentric with the .axis of rotation of the door 9 when the switch is in open position.

Y The door 9 is provided with a cani meinbei' 43 having a convex edge concentric to theV axis of rot-ation of the door 9 and a concave edge 44 that is vconcentric to 'the axis of rotation of the shaft 23 when the door is in closed position. ByA reason of the arrangement of the cam members 39 and 43,'which` are disposed in the same plane exteriorly of the housing, opening movementl of the door is prevented'so long as the switch is in the closed position indicated in Fig. 2. By reason ofthe engagement of the concave surface 44 with the arcuate edge 41 of the cam `member 39, opening.` movement of the cover 9 is precluded until after the switch has moved into extreme open position wherein the caminember 39 clears the cam 43 and permits opening movement of the door.

- Vhen the door is moved slight-ly out vof closed position,`the corner 45 of the cani member 43 is vmoved across the path of movenient of the cani member 39 and prevents closing movement of the switch. The switch cannot be closed, therefore, so longl as the door is in any other than fully .closed position. Y

As the pressure,y generated in the housing by an explosion of mine gases therein, is :extremely high, it is necessary'to provide ampler means for securingthe door in closed position so that the door provides a tight seal which permits the gases to escape gradually and which cools Vthem suiiiciently .to extinguish them before they reach the atmosphere. VI have, therefore, provided a rotatable lock plate 46, Fig. 5, mounted upon a shaft 47 that projects exteriorl-y of the door and is provided with an'operatinghandle 48. The.` plate is provided with three arcuate slots 49 adjacent tlieperipheral edge thereof through which extend stationary rivets 51 that aresecured to the inner side of thedoor. f

Y The rivets aie iprovided withy enlarged heads 52 that serve to `support the plate against longitudinal displacementv The plate is provided with latch extensions 53 that project beneath lugs` 54 that are boltedv in slots provided in the edge fiange of the housing. Vhen the plate 46 is in the locked position indicated in Fig. 1, the extensions lli) lll

fi and a collar 62 secured to the bar.

53 engage the inner surfaces of the lugs 54 which are inclined slightly and serve to cam the door tightly in closed position.

The plate 46 isprovided with a notch 55 that is adapted to receive the end 56V of a latch rod 57 that is slidably mounted upon the underside of the door and secured thereto by means of clips 58. The end of the bar adjacent the switch is provided with an inwardly-turned end 59 that is adapted to be engaged by the operating rod 19 and moved thereby when the rodis moved to closed position. Movement oi the rod to the right causes the end 5G to engage the slot 55 in the Z plate 4-6 and prevent rotary movement of the plate so long as the switch is in closed position.

A helical spring Gl surrounds the rod 57 and is disposed between one of the clips 58 This spring normally tends to move the latch bar 57 out ot engagement with the slot 55 when the switch is moved to open position.

It is apparent, therefore, that the latch plate t6 can not be moved to release the lcover so long as the switch is in closed position. Therefore, there is no danger 0Ip gaining access to the interior oi' the housing eX- cept when the switch is in open position.

in order to insure that the joint between the stationary portion of the cover 7 andthe door 9 is substantially gas tight, the tree edge of the cover '7 is provided with a tongue 63 that snugly tits the groove 64. This con- "Ia struction provides a tortuous passage for theV escaping gases.

It is understood that no attempt is made to absolutely preventthe escape of gases from the housing, it being the purpose only to prevent the ignited gases from escaping `from the housing before they are extinywithout departing from the spirit and scope invention as set forth in the appended ble locking plate on the door slidably sups ported at a plurality of points respectively adjacent to the other edges of said door and having portions adjacent to each of the points ot' support for engaging the housing whereby all ot' the edges of the door may be secured in closed position and means for interloclring the said plate with the switch whereby opening movement of the plate is prevented so long as the switch is in closed position.

2. Switch mechanism comprising a housing, a movable switch within the housing, a door hinged at one edge to the housing, a locking member rotatably mounted on the door and secured thereto at points adjacent to the other edges and engaging the housing adjacent to each of said points for retaining the door in closed position, and an interlock rod slidably mounted on the door and actuated by the switch for engaging the locking member and for preventing opening movement' thereo'tl so long asthe switch is in other than fully open position.

3. Switch-mechanism comprising a housing, a movable switch within the housing, a door hinged at one edge to the housing, a locking member rotatably mounted on the door for engaging the housing and retaining the door in closed position, the said member being provided with a radial slot, and an interlocking rod slidably mounted upon the cover and movable by the switch into the slot when the switch is moved to closed position for preventing releasing movement ot' the locking member. j

In testimony whereof, I have hereunto subscribed my name this 17th day of April,

.HAROLD G. BAXTER. 

